As I write this, the U.S. is just hours away from its 18th government shutdown over the last 35 years. Beyond expectations, House Republicans are sticking to their guns and insisting that President Obama and Senate Democrats make changes to the unpopular ObamaCare law before authorizing further government spending. As I prepare the bottle-rockets for launch at midnight, it is wise to recap what isn't affected by a government shutdown.

So, without further ado, the top 5 things that won't shutdown on Tuesday:

5. Air Traffic control/TSA airport security

Any government function related to public safety is exempt from shutdown. Air traffic controllers will still be at their posts on Tuesday. Fortunately/Unfortunately, TSA security guards will still be many airport security across the country. Air travelers ought not to experience any extra delay due to a government shutdown.

4. Social Security/Medicare

Social Security, Medicare, Medicaid, disability and VA benefits are mandatory spending items not subject to annual Congressional appropriations. As such, seniors will still receive their pension checks and have access to health care. Veterans will still receive the benefits they earned. There may be a delay in processing new claims for benefits, but it will be just that...a delay.

3. Law Enforcement/Border Security

To the extent the Obama Administration even enforces the border anymore, those activities will continue. The FBI, ATF and DEA, for better or worse, will also remain at their guard-posts. Criminals thinking a government shutdown is a ripe opportunity to ply their trade will get a rude awakening. Only about 15% of the Department of Justice workforce will be furloughed.

2. The Military

Even without Congressional action, troops serving overseas would continue to be paid in a government shutdown. On Monday, however, the House sent language to the Senate that would ensure that everyone serving in uniform would continue to be paid. The Senate has adopted this language and President Obama is expected to sign it into law late Monday. Men and women in uniform will be paid, although the outlook for defense contractors is less clear.

1. ObamaCare

Ironically, the issue that has propelled the US to a government shutdown, ObamaCare, will carry on. Over 70% of the law is funded by mandatory spending, which always made the "defund" fight more political theater than anything else. On Tuesday, the ObamaCare health care exchanges open to the public, even as the rest of the government closes its doors. How the roll-out proceeds may determine whether the GOP strategy to tie government funding to a delay in ObamaCare is a political winner. Hint: Probably so.

Tuesday ushers in a new day in our budget and fiscal debate. Most of what Americans value as a true government function will remain open. The more ambiguous parts of government will close. It will be interesting, after a week or so, to see how much the public misses those parts.